This third and final volume of the logbook presents the work on “The Color of Water”, a series parallel to Initium Maris but parts of which were integrated into the expedition. This notebook also brings together several texts with artistic or scientific entries, views of the first exhibitions as well as the presentation of the educational module “Initium Maris-Civis”. The artistic expedition ​ “ Initium Maris”, is part of the Paysages Productifs series, an inventory of underwater landscapes of the French coasts started by Nicolas Floc’h in 2015. Initium Maris and Paysages Productifs propose to show, from a photographic point of view, what extends beneath the surface as far as the eye can see; to question the representations that are made of the ocean; to carry out an inventory of landscape typologies at a given time; to disseminate this work in the world of art, but also in the most diverse environments: scientific, civic, educational communities... Nicolas Floc'h's photographic series Paysages productives brings together a set of projects on the representation of underwater landscapes and habitats and their role as productive ecosystems, the fabric of life. Essential indicators of major societal issues, the color of the ocean and the state of the landscapes make it possible to visualize phenomena such as the modification and habitability of environments. They also discuss the regulation and transformation of the climate, the degradation and preservation of biodiversity and in fact, a global approach to the biosphere. Productive Landscapes is made up of the series: Ouessant (2016), The color of water (since 2016), Kuroshio (2017), Initium Maris (2015−2022), Initium Maris – Deep sea (2021), Bulles (2019), Invisible (2018−2020), Invisible/Parallèle – Port-Cros (2020), Invisible/Parallèle – Lérins Islands (2021).